The drift current across a p-n junction during its formation is

The correct answer is Option (2) → from the n-side to the p-side

While the junction forms, electrons diffuse from n to p and holes from p to n, giving the diffusion current from the p-side to the n-side. The ions left behind set up an electric field in the depletion region, pointing from n to p.

This field makes minority carriers drift: holes from n to p and electrons from p to n. Both give a conventional current along the field, so the drift current flows from the n-side to the p-side.

Why the other options are incorrect

• Option (1) from the p-side to the n-side — Incorrect. This is the direction of the diffusion current. The drift current is opposite to it.

• Option (3) zero — Incorrect. Once the depletion field appears, the drift current is not zero. In equilibrium it equals the diffusion current, so the net current is zero.

• Option (4) initially large compared to diffusion current — Incorrect. At the start the field is weak, so the drift current is small compared with the diffusion current. It grows until the two are equal.

NCERT (2026-27):
p-n Junction Formation – “… Due to this field, an electron on p-side of the junction moves to n-side and a hole on n-side of the junction moves to p-side. The motion of charge carriers due to the electric field is called drift. Thus a drift current, which is opposite in direction to the diffusion current (Fig. 14.10) starts.”

p-n Junction Formation – “… Initially, diffusion current is large and drift current is small.”